Refrigerated equipment



2 Sheets-Sheet l INVENTOES;

June 30, 1970 M. D. MaCMAsTER ETAL REFRIGERATED EQUIPMENT Filed Aug. 9, 1968 E* I rf )I Musa/14 @MAW/:575,2 F'g- & l/.mser ,Q Maze/s June 30, 1970 y M D, MacMAsTr-:R ETAL 3,517,526

REFRIGERATED EQUIPMENT Filed Aug. 9, 1968 :3 Sheets-5heet 2 MLC'OLM MCMST-Q NVENTRS. 8 Hfeer )Q MQgQ/g United States Patent Ciiice Patented June 30, 1970 3,517,526 REFRIGERATED EQUIPMENT Malcolm D. MacMaster, Yardley, and Herbert R. Morris,

Morrisville, Pa., assignors to Emhart Corporation,

Bloomfield, Conn., a corporation of Connecticut Filed Aug. 9, 1968, Ser. No. 751,582

Int. Cl. A4f 3/04 U.S. Cl. 62-256 8 Claims ABSTRACT F THE DISCLOSURE A refrigerated display case embodying an insulated er1- closure having an access opening in the front thereof with means for establishing an air curtain including a plurality of layers of air directed across the access opening from an upper and outer air discharge opening and a lower and inner air discharge opening. A member presenting an arcuate air guiding surface is located between the air discharge openings and terminates in a lower edge adjacent the outer side of the lower and inner air discharge opening.

FIELD OF INVENTION The use of air curtains to oppose the entry of ambient air through an access opening into a refrigerated space in a display case is well known in the art. For this purpose it is frequently desirable to employ a plurality of layers of air having different temperatures in establishing the air curtain in order to limit the penetration of warm moist air into the inner and colder layer of air circulated adjacent the interior of the case. However, turbulence and undesired intermingling of the air layers tends to occur in the event a dead air space develops between the adjacent layers of air.

It is further desirable in many cases to cause the air curtain to flow downwardly across the access opening in close proximity to the outer edges of shelves by which articles are supported within the display case.

In accordance with the present invention the creation of a dead air space and resulting intermingling of the layers of air in an air curtain are avoided by providing air discharge means having a novel construction and arrangement. In the preferred construction herein shown and described the air discharge openings are displaced vertically and horizontally from each other whereas an air guiding surface is interposed between such openings to lead a layer of air issuing from an upper and outer opening into contact with a second layer of air immediately upon issuance thereof from a lower and inner discharge opening. It is further preferred to shape the portions of the air ducts directly in advance of the discharge opening so that they are reduced in cross section in a direction transverse to the layers of air produced thereby. The discharge openings also may be so directed as to cause the air curtain developed to flow downward in close proximity to the outer edges of shelves within the refrigerated display space.

THE DRAWINGS PREFERRED yEMBODIMENT OF THE INVENTION In that form of the invention chosen for purposes of illustration in the figures of the drawing the refrigerated display case embodies an insulated enclosure 2 having a display space 4 therein provided with an access opening 6 in the front wall thereof. An air curtain or air barrier is established adjacent the access opening for limiting or preventing the entry of warm, moist ambient air into the display space through the access opening. For this purpose at least two air ducts 8 and 10 are provided and means such as blowers 12 and 14 respectively are employed for circulating air through the air ducts from return air inlet means 16 located adjacent the lower edge of the access opening to a lower and inner air discharge opening 18 and an upper and outer air discharge opening 20, both of which are located adjacent the upper edge of the access opening. The lower inner air discharge opening 18 is provided with a grill or a honeycomb type of air straightening means 22 which preferably is inclined slightly inwardly toward the shelves 24 on which articles are supported within the display space 4. The upper and outer air discharge opening 20 is similarly provided with a grill or honeycomb type air straightening means 26 which may serve to direct air vertically downward from the opening 20.

Refrigerating means 23 are utilized for reducing the temperature of the air circulated through one or both of the air ducts 8 and 10 but in any event the temperature of the air circulated through the inner air duct 8 and discharged through the lower and inner air discharge opening 18 should be lower than that of the air circulated through the outer air duct 10 and the upper and outer air discharge opening 20. The air curtain thus established embodies an inner colder layer of air 28 which serves to maintain the articles on shelves 24 at the desired low temperature and an outer protective layer of air 30 having a temperature intermediate that of the air layer 28 and the ambient air which serves to minimize the transfer of heat and moisture from the ambient air to the air within the display space.

In order to prevent the formation of a dead air space between the two layers of air 28 and 30 in the zone between the air discharge openings 18 and 20 and at the point where the two layers of air merge to form the air curtain, a member 32 is located between the air discharge openings and is formed to present an arcuate air guiding surface 34 over which the air issuing from the upper' and outer air discharge opening 20 is caused to flow. The upper portion of the surface 34 curves forwardly and downwardly from the inner side of the air discharge opening 20 whereas the lower portion of the surface 34 curves inwardly and downwardly to the outer side of the air discharge opening 18. The portion 0f the inner colder air duct 8 adjacent the air discharge opening 18 presents an inner upper surface 36 which is inclined downwardly so that the duct is reduced in its cross sectional area t0-` ward the outer side of the air discharge opening 18. The outer and ywarmer air duct 10 is similarly formed to present an inner upper surface 38 inclined toward the outer side of the air discharge opening 20.

With this construction the velocity of the air issuing from the outer side of the air discharge opening 18 and forming the outer portion of the inner cold air layer 28 of the air curtain will be greater than the velocity ofl that portion of the inner layer of air which is adjacent the refrigerated space 4. The turbulence and intermingling of the cold air layer with the air within the display space is thus reduced and refrigeration losses are minimized. On the other hand, the forwardly and downwardly curving upper portion of the air guiding surface 34 projects beneath the inner side of the outer air discharge opening 20 and serves to reduce the effective cross sectional area of the outer discharge opening. As a result the velocity of the air flowing over the air deecting surface 34 and forming the inner portion of the outer layer of air 30 of the air curtain is increased so that it may eaual nr approach the velocity of the inner layer of air 28. Turbulence and intermingling of the two layers of air 28 and 30 is thereby reduced. n

The increase in velocity of the inner portion of the outer layer of air issuing from the air discharge opening further serves to cause such air to flow downwardly and to follow closely adjacent the lower and inwardly curved portion of the air guiding surface 34 to a point adjacent the lower edge of said surface. The action of the inner portion of the outer layer of air 30 in following the inwardly curved lower portion of the air guiding surface 34 may be due in part to the lateral expansion of the air layer after it passes the restriction of the outlet 10 imposed `by the outwardly and downwardly curved upper portion of said surface. In any event the two layers of air 28 and 30 are caused to merge into direct contact im- -mediately adjacent the outer side of the lower and inner air discharge opening 18. The formation of a dead air space between the two layers of air is thereby precluded and undesired turbulence and intermingling of the layers with each other is reduced to a minimum.

As indicated above, the air discharge opening 18 may be provided with a honeycomb or other air straightening means 22 which serve to reduce the turbulence of the air issuing from the outlet opening after being directed downwardly from the horizontally extending air duct 8.

The honeycomb 22 preferably is tilted slightly to cause inner surface inclined downwardly toward the outer side the air forming the inner layer of air 28 of the air curtain to flow downwardly adjacent the front edges of the shelves 24 within the display space 4. On the other hand, it has been found in practice that the honeycomb member 26 in the outer air discharge opening 20 may be directed vertically downward without creating any dead air space between the air layers 28 and 30. As a result the outer layer of air 30 serves to oppose any tendency for the air curtain to be deected so far inwardly by the ambient air pressures to impair the pattern of the air flow by direct contact with the shelves 24 or articles displayed thereon.

While a preferred embodiment of the present invention has been illustrated in the drawing and described above, it will be apparent that numerous changes and modifications may be made in the form, construction and arrangement of the various elements without departure from the invention.

We claim:

1. A refrigerated display case having a display space therein provided with an access opening in the front thereof, means for establishing an air curtain across said access opening including two air ducts communicating with air inlet means located adjacent the lower edge of the access opening, one of said ducts having an upper and outer air discharge opening near the upper edge of the access opening and the other of said ducts having a lower and inner air discharge opening also located near the upper edge of the access opening, means for circulating air through said air ducts, means for refrigerating the air circulated through at least one of said air ducts, and means presenting an arcuate air guiding surface extending downwardly from a point adjacent the inner side of said upper and outer air discharge opening to a point adjacent the outer side of said lower and inner air discharge opening.

2. A refrigerated display case as defined in claim 1 wherein said upper and outer air discharge opening at least partially overlaps said lower and inner air discharge opening.

3. A refrigerated display case as defined in claim 1 wherein at least one of said air ducts has a portion thereof near its associated air discharge opening which is reduced in cross section toward the outer side of its air discharge opening.

4. A refrigerated display case as defined in claim 1 wherein the portion of at least one of said air ducts adjacent its associated air discharge vopening presents an upper inner surface which is inclined downwardly toward the outer side of its air discharge opening.

5. A refrigerated display case as defined in claim 1 wherein that portion of each of said air ducts adjacent its associated air discharge openings presents an upper of its air discharge opening.

6. A refrigerated display case as defined in claim 1 wherein at least one of said air discharge openings is inclined inwardly toward the display space within said case.

7. A refrigerated display case as defined in claim 1 wherein the upper portion of said air guiding surface curves forwardly and downwardly from the inner side of the upper and outer air discharge opening and the lower portion of the air guiding surface curves downwardly and inwardly toward the outer side of the lower and inner air discharge opening.

8. A refrigerated display case as defined in claim 7 wherein the portion of each of said air ducts adjacent its associated air discharge opening presents an upper inner surface inclined downwardly toward the outer side of its air discharge opening.

References Cited UNITED STATES PATENTS 3,063,256 11/1962 Lamb 62-256 WILLIAM J. WYE, Primary Examiner U.S. Cl. X.R. 98-36 

